Samuel Thibault wrote: [snip] >>No, in windows there is a requirement that mmap uses memory aligned to 64k >>(the >>infamous granularity). > > Then the result of pagesize() is not sufficiently big: POSIX says that > mmap() can return EINVAL if « the address [...] is not a multiple of > the page size, or is considered invalid by the implementation ». Well, > we could consider non-16-pages-alignment as `considered invalid', but I > guess this expression was meant as `not in a mmap()-able area'.
mmap() is returning an error code, probably EINVAL I just ddisn't care to look what was it because there shouldn't be an error. [snip] > 16 pages > are still not enough: if malloc() returns 0x0001 for instance, you'll > round up that to 16*pagesize, which is out the allocated area. 17 pages > are necessary. Yes, that would produce an error... not the one you are saying but the "aligned" result will fall at the end with less than a pagesize available for mmap. > BTW, I don't understand why using so complicated code: > p += (align - ((long) p & (align-1))) & (align-1) > Isn't > p = ((long) p + (align-1)) & (align-1) > both faster (tested) and more readable ? I didn't write the original code, it is from gcc-4.0.2 and it's used all over the place to make libraries (libstdc, libgcj, perhaps others) and tools. There are other mmap() tests that fail (mmap from /dev/zero, mmap with MAP_ANON) I'm just starting to look around to see what is the problem, and perhaps send a patch to the gcc maintainers so we can have a fully functional set of libraries. Regards. -- René Berber -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
